Guren, Ceylan, Chooki and Toxsa aren't really humans.
What if years before the series started Guren and the other boys were the original Tenkai Knights, but after being fatally wounded in their efforts to stop the rampaging Tenkai Dragon, their Tenkai Energy left Quarton to find sanctuary on earth in human form, effectively becoming humans. Where the boys each found in infant form and were all taken in by the people who would become their parents.
It's hinted that Villius may actually be a pawn to a greater evil that Dromas is actually aiding.
- Seems Guardian Eurus could be that bigger bad.
Mr. White, and possible Beni's father, were members of the original Tenkai Knights
Instead of being destroyed, the Knights were sent to Earth. While Mr. White was content with his life as a human and decided to find suitable replacements, Beni's father become obsessed with returning, even ignoring his new life and family.